Scientists from Argentina and Brazil said the Patagonian dinosaur appears to represent a previously unknown species of Titanosaur because of the unique structure of its neck. They named it Futalognkosaurus dukei after the Mapuche Indian words for "giant" and "chief," and for Duke Energy Argentina, which helped fund the skeleton's excavation.

"This is one of the biggest in the world and one of the most complete of these giants that exist," said Jorge Calvo, director of the paleontology center at the National University of Comahue, Argentina. He was lead author of a study on the dinosaur published in the peer-reviewed Annals of the Brazilian Academy of Sciences.

Scientists said the giant herbivore walked Earth some 88 million years ago, during the late Cretaceous period.

Since the first bones were found on the banks of Lake Barreales in the Argentine province of Neuquén in 2000, paleontologists have dug up the dinosaur's neck, back region, hips, and the first vertebra of its tail.

"I'm pretty certain it's a new species," agreed Peter Mackovicky, associate curator for dinosaurs at Chicago's Field Museum, who was not involved with the discovery. "I've seen some of the remains of Futalognkosaurus, and it is truly gigantic."

Calvo said the neck alone must have been 56 feet (17 meters) long, and by studying the vertebrae, they figured the tail probably measured 49 feet (15 meters). The dinosaur reached more than 43 feet (13 meters) tall, and the excavated spinal column weighed about 9 tons when excavated. One neck vertebra alone measured more than 3 feet (a meter) high.

Jeff Wilson, an assistant professor of paleontology at the University of Michigan who was asked to review the finding, said he was impressed by the sheer amount of skeleton recovered.

"I should really try to underscore how incredible it is to have partial skeleton of something this size," Wilson said in telephone interview. "With these kind of bones you can't study them by moving them around on the table; you have to move around them yourself.

"It shows us the upper limit for dinosaur size," Wilson added. "There are some that are bigger, but they all top out around this size."

Patagonia also was home to the other two largest dinosaur skeletons found to date—Argentinosaurus, at around 115 feet (35 meters) long, and Puertasaurus reuili, 115 feet to 131 feet (40 meters)long. (See a photo gallery of Puertasaurus reuili.)